DESCRIPTION: Dysarthria is a frequent result of several neurological disorders, including Parkinson disease, stroke, cerebellar pathologies, multiple sclerosis, and traumatic brain injury. Dysarthrias often lead to decreased speech intelligibility, but they also affect other dimensions of spoken language, including voice quality, prosody, and paralinguistic features. These have not been studied collectively in large numbers of individuals with dysarthria. This project uses a multiple-task protocol with both perceptual and acoustic measures to examine intelligibility, voice quality, prosody, and paralinguistic aspects in children and adults with acquired dysarthria. Several newly developed analyses will be used to provide quantitative data toward the construction of profiles of speech impairment and neurologic lesion. Included will be the first systematic replication of the original work that led to the contemporary classification of the dysarthrias. The data on dysarthria will be integrated with data on speech development and normal adult speech in a neural network model of speech production that is based on internal models of auditory and articulatory representations of speech.